Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N37/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom having three bonds to hetero atoms with at the most two bonds to halogen, e.g. carboxylic acids
  • A01N37/34—Nitriles

Definitions

• This invention relates to biocides used in hydrocarbon production from subterranean formations.
• it relates to a formulation for enhancing the solution rate of 2, 2-dibromo-2-nitrilopropionamide.
• DBNPA 2,2-dibromo-2-nitrilopropionamide
• DBNPA is slow to dissolve, however, in many practical field situations. Its normal solubility in water is about 1.5%. Because its rate of solution is slow, it has been prepared as a powder or used in other small particulate form rather than pellets, to expose more surface area to the available water, but this approach is not always successful. Frequently the DBNPA is simply added to a tank or large vessel of water in the field where there is no convenient way to agitate it, and accordingly the user must rely on the unaided solution rate to dissolve the material. Even a finely divided powder resists dissolving in a useful period of time in a quiescent container of water.
• a better method of dissolving DBNPA is needed for use in locations not having convenient agitation apparatus.
• DBNPA 2,2-dibromo-2-nitrilopropionamide
• the composition includes a major portion of DBNPA, and smaller portions of sodium bicarbonate and citric acid, with an optional amount of borax.
• This composition will tend to generate carbon dioxide when it is exposed to water, causing its own agitation or physical movement in the water. Not only is a high percentage of the DBNPA exposed to the water quickly by the dissolution of the other ingredients, but it is physically exposed to more water by movement through the water caused by the effervescence of the gas generation. The material accordingly dissolves quickly and efficiently
• my invention comprises a composition for delivering the biocide DBNPA to an oilfield fracturing fluid comprising, in tablet form, DBNPA and an amount of effervescent ingredients effective to cause agitation and breakup of the tablet on contact with water.
• My method comprises dispersing DBNPA in water and/or an aqueous medium such as a fracturing fluid containing water by combining it with effervescing agents and placing it in the water or fracturing fluid together with the effervescing agents, in the form of a tablet.
• Compressing the ingredients in the form of a tablet makes the composite dense, so that the tablet will sink in a quiescent liquid.
• a stock tank near a well may have in it both oil and water, which rests quietly in the lower portions of the tank.
• the pellet or tablet will readily pass through the oil and begin effervescing on contact with theotherwise still water, providing its own motion and enhanced contact with the water; it is thus able to disperse the biocide where it is needed -- in the lower regions of the tank.
• the tablet will be able to sink to the "ratholes" and other relatively inaccessible areas of wells.
• the tablets are also useful in the quiescent water often found in fracturing fluid tanks and similar applications in the oilfield where fresh water is pumped into a reservoir. Frequently such fluids are mixed with organic gel-forming agents such as polysaccharides, which are readily metabolized by bacteria.
• DBNPA 100 tech
• sodium bicarbonate 20% citric acid
• borax 10% borax. This is the presently preferred composition, but it may be varied as follows: (by weight) DBNPA: 35-65%; Na 2 (CO 3 ): 15-28%; citric acid: 15-27%; borax: 0-20%.
• a tablet weighing about 22g and made of the above preferred formulation was dropped into a jug of tap water at 58°F having a column height of 14 inches.
• a trace of snow-like particles dispersed in the water was observed within about two minutes; these were assumed to be active DBNPA released as a result of the effervescing.
• the effervescence of the tablet was believed to have caused minor turbulence of the water in the vicinity of the tablet, which in turn caused the dispersion of the particles throughout the water.
• Example 1 A tablet similar to that of Example 1 was dropped into a 4 liter beaker containing three-quarters of an inch of water; then additional water was added slowly to the beaker, in simulation of an oilfield fracturing fluid tank. Observations of the dispersed material were similar to those of Example 1.
• Tablets similar to those used in Examples 1 and 2 were added to equal quantities of tap water, sea water, and a saturated solution of sodium chloride.
• the tablet effervesced and dissolved rapidly in the water and the sea water, but was somewhat weaker in effervescence and slower in dissolution in the brine.
• My invention is not limited to the specific effervescing agents mentioned herein. Any combination of effervescing agents which will cause an evolution of gas is satisfactory; those which are more vigorous are preferred. The amount should be effective to cause agitation and breakup of the tablet on contact with water.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Agronomy & Crop Science (AREA)
• Pest Control & Pesticides (AREA)
• Plant Pathology (AREA)
• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Dentistry (AREA)
• General Health & Medical Sciences (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Environmental Sciences (AREA)
• Medicinal Preparation (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)

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Publications (1)

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Cited By (4)

Citations (4)

• 1999
  • 1999-02-19 EP EP99103320A patent/EP0953284A1/fr not_active Withdrawn

Patent Citations (4)

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